Centerless grinding machine



Feb, 3, 1925. 1,524,969

5. EINSTEIN ET AL CENTERLES S GRINDING MACHINE Filed Jan. 28, 1924 3Sheets-Shet 1 gnvenlfou. 252 6 2'22 Gtkotnega Feb. 3, W25.

5. EINSTEIN ET AL CENTERLESS GRINDING MACHINE Filed Jan. 28, 1924 3 Sheets-Shem. 2

Feb. 3, 1925. 1,524,969

s. EINSTEIN ET AL CENTERLESS GRINDING MACHINE Filed Jan. 28, 1924 Sheets-Sheet 5 Patented Feb. 3, 1925,

UNITED STATES "PATENT OFFICE.

SOL EINSTEIN AND LESTER F. NENNINGER, OF CINCINNATI, OHIO, ASSIGNORS TO THE CINCINNATI MILLING MACHINE COMPANY, OF CINCINNATI, OHIO, A COR- PORATION OF OHIO.

. CENTERLESS GRINDING MACHINE.

Application filed January 28, 1924. Serial No. 689,067.

To all whom it may concern:

Be it known that We, S01. EINSTEIN and LESTER F. NENNINGER, citizens of the United States, residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Centerless Grinding Machines, of which the following is a specification.

This invention pertains to centerless grinding machines, and contemplates in its preferred and most complete embodiment a self-contained structure, which, with work. rests and attachments set forth in copending applications, is capable of grinding plain or straight cylinders without head, shoulders or projection of any kind, by a continuous operation, in which, by reason of slight inclination of the axis of the governing or control wheel relative to that of the grinding wheel and to that of the work, the work is caused to move axially over the abrading surface of the grinding wheel at predetermined and uniform rate of advance; or under parallel adjustment of the govern ing wheel and grinding wheel axes, will grind to any depth desired, the grinding stopping when the predetermined limit is reached, and this Whether the work be headed, shouldered, or of a plurality of diameters at difierent points in its length, and which, finally, with proper dressing of the grinding and governlng wheels, will grind tapered work, all with greatest precision and accuracy.

When grinding headed, or shouldered or tapered work, the spiral feed is not, ordinarily, employed, but the work is introduced manually, or automatically, the grinding and governing wheels being separated sufficiently to. facilitate such placing of the blanks or objects to be ground, and thereafter gradually approached, are toward the' outer until the requisite amount is cut away,

whereupon, either manually or through mechanical devices, actuated manually or automatically, the ground object is ejected, this cycle of operations being repeated as long as like objects are to beground. I

The foregoing statement is made to point the necessity for, and the special and the peculiar advantage of change speed gear with wide range variations, in a grinding machine of the character set forth. It renders possible both classes and methods of the work ejecting devices, manual or auto matic, or the automatic feed devices shown in detail, some not shown at all. The pres e-nt application is confined mainly to means for varying the speeds of the grinding and governing wheels and the relative speed ratios of said wheels, to suitobjects of vary- 1ng diameters form, character, and material, and mode of grinding, and to mechanism for advancing and receding the governing or control wheel toward and from the grinding wheel, work rest and work.

These features are. illustrated in the accompanying drawings in which- Figure 1 is a. side elevation of the grinding machine, with the driving belts, chain, leather or other, indicated by dotted lines, as are also, in outline, the change-speed gears; 'Fig. 2 is an end ;view of the machine look- 1ng at the governing or control wheel end:

Fig. 3 is a vertical sectional view on the line 3 3 of Fig. 2, showing the change speed gear in side or face elevation;

, Fig. 4, a sectional view of the change speed gear train, developed in plane;

Fig. 5, a perspective view of the yoke in which certain gears are carried and by which they are shifted laterally and swung into meshing relation with transmitting gears of varying diameters. The grinding machine in its preferred embodiment is of the general appearance shown in Fig. 1,'comprising a main frame or base 1 upon which are carried a grinding wheel 2 and a governing or control-wheel 3, as also an interposed work-rest 4 provided with a work-supporting and guiding bar or plate 5, which latter will vary in form according to the character, form, size, and other conditions of the particular ob ject to be ground. interchangeable bars or plates being provided to meet such varying conditions. The grindin wheel 2 is carried upon a spindle or ar or whichis preferably secured fixedly tothe top or bedplate of the main frame 1 in order to secure the utmost rigidit and freedom from vibration, though if esired the grinding wheel support may be made adjustable toward and from the governing wheel and its support or carrier. The governing wheel support is preferably and usually made adjustable toward and from the grinding wheel and its support, and this will advisably be done whether or not provision be made for adjustment of the grinding wheel and its support.

The governing or control-wheel support comprises a carrier 6 movable upon ways on a slide 7, which slide in turn is movable upon ways on the top-plate or bed of the main frame, all as indicated by dotted lines in Fig. 1 and in end View, Fig. 2. The carrier 6 and the slide 7 are furnished with clamping devices 8 and 9 respectively, by which the'carrier may be locked to the slide, and the slide locked to. the ways on the bed, or by which either or both may be released at will from their slideways. Any usual form of clamping device may be employed a simple screw-stem passing through the side wall of the guiding rib of the moving part and bearing against the side wall of the companion guide rib, or against a gib or plate interposed between such wall and the opposing wall of the guided member, being illustrated in the drawing.

The journal hearing or sleeve in which the spindle or arbor of the governing wheel 3 rot-ates is carried by a housing member 10, connected with or attached to the carrier 6 by a horizontal pivot, the axis of which is preferably coincident with a line passing through the true centers of wheels 2 and 3, that is to say, through the centers of their masses, so that though the governing or control-wheel 3 be tipped about such pivotal axis its true center will not be shifted. The meeting faces of the carrier 6 and housing 10 are at their top curved concentrically with the axis of the pivot of said housing, and are at such point of equal radius, so that graduations 11 formed upon one of said parts may be read in connection with a fixed point or mark 12 on the other part, thus enabling the attendant of determine accurately the angle to which the governing wheel shall be tipped. A clamping bolt 13 passing through a curved opening in the attaching base or plate of housing 10 and screwing into the proximate face of carrier 6, serves to clamp or bind the housing to the carrier, provision being also commonly made for tightening the pivot connection to make the attachment as rigid as possible. These details constitute no part of the present invention, but are recited simply to make more clear the usual adjustments of a. grinding machine of the class referred to, with the purpose of affording a better understanding of the part played'by the change-speed gear in its combination with such machine.

Referring again to Fig. 1, the numeral 14 indicates the main driving shaft of the machine, which in practice it is preferred to drive by electric motor attached directly to the frame or base 1 of the machine at a point in proximity to said shaft. The employment of such motor renders each grindmg machine absolutely complete in itself or self-contained, and enables any selected speed of the grinding wheel and of the governing wheel, determined by the changespeed mechanism, to be maintained constant, whereas machines driven from a countershaft are subject to variation in speed incident to the varying load placed upon the counter-shaft through bringing in or cutting out individual machines. Maintenance of a sufi'iciently high speed of the grinding wheel, and constancy or uniformity of speed of the grinding and of the governing wheels, and of the ratio of speeds of said wheels, are matters of vital importance in grinding machines of this character.

Mounted upon shaft 14 is a pulley 15 to receive a drlving belt 16 carried about a belt-pulley 17 on the shaft or arbor of the grinding wheel 2. The belt 16, in the arrangement here illustrated, is an open belt which may be tightened by a tightener-roll 18 mounted in a swinging support 19 ressed by a screw 20 into contact with Sitld. belt '16. 21 indicates a sprocket-wheel, or if a driving belt instead of a chain be used, a belt pulley, secured upon shaft 14, and connected by chain 22, or belt, with a sprocketwheel 23, or belt pulley, carried in bearings in the main frame 1, and here shown as located at the end of said frame remote from that at which the shaft 14 and its journal bearings are located.

\Vheel 23 is carried by a shaft- 24, which with the change-speed gear here illustrated, is the topmost one of a series of shafts each carrym Through the gear train just referred to rot-ary motion is imparted to a shaft 25journaled in bearings in the main frame of the machine, and carrying a belt-wheel 26 about which passes a belt 27, the two stretches of which pass over idler pulleys 28 and 29 carried by a swinging frame 30 connected by a link 31 with a threaded stem 32 adjustable axially by a swivel nut 33 formed or furnished with a hand-wheel 34. As a nut 33 is held against endwise movement and screw 32 is prevented from rotating by its connection with the tightenerframe 30, rotation of the hand-wheel and nut will of course effect a swinging of said frame, thus pressing the rolls 28 and 29 more or less firmly gear wheels as presently described.-

considerable traverse of the carrier 6 and consequently of the governing or controlwheel 3, toward and from the grindlng wheel without material or appreciable tightening or slacking of the belt.

The variable-speed gear train serves to effect varying ratios of speed between shafts 24 and 25. This may be accomplished by any well-known variable-speed gear affording a desirable number of changes. That illustrated in the drawings allows sixteen changes of the governing or control-wheel speed, varying from 16 to 442 revolutions per minute of said wheel, but while this is found a very satisfactory number and range, it is to be understood that more or fewer changes may be provided, and that the ratios may be varied. It is obvious also'that where an electric motor is employed to rotate the shaft 14, its speed, and consequently all speeds derived therefrom, may be increased or diminished by use of ,a rheostat without affecting the speed ratios of the grinding and governing or control wheels. v

Referringnow to Figs. 3, 4 and 5 the details of the speed-change gear will be explained. Shaft 24 is journaled in bearings 36, conveniently formed as bushings and secured in openings in substantial brackets 37 projecting inward from the inner face of a detachable cover-plate 38, screwed or bolted to the end of the base or main frame, as shown in Fig. 2 and indicated by dotted lines in Fig. 4. imilar bushings or bearings 39 carry the journals of a shaft 40 parallel with and below the shaft 24. A third shaft 41 parallel with shafts 24 and 40 is journaled at one end in a suitably bushed bearing 42 formed in a head 43 fixed in a circular seat in one end of a housing44 formed integral with and projecting inward from the coverplate 38, as seen in Fig. 3.

Slidable longitudinally upon the body of shaft 41 is acylindrical sleeve 45 carrying at its midlength a projectingyoke 46 of the form best shown in Fig. 5, the two walls of said yoke standing on opposite sides of an opening 47 formed in the sleeve 45 at its midlength to permit the introduction of a pinion 48 which meshes with a gear. 49 carried by a shaft or axle 50 in bushings or bearings located in the side walls of yoke 46. Shaft 41 is longitudinally grooved to receive a spline or feather carried by the pinion 48, so that said pinion may freely slide lengthwise of said shaft but may not rotate thereon or independently thereof. The ends of the sleeve 45 are supported and guided in,

projecting Sleeve 45 affords a support and bearing for shaft 41.

For the purpose of moving the sleeve 45 axially and thereby shifting the intermeshing gears 48 and 49, said sleeve is provided with a projecting arm 51 having at its outer end a tubular barrel 52 within which is seated a longitudinally movable bolt 53, the reduced stem of which bolt extends outward beyond the barrel 52 and passes through a nut 54 screwed into the open outer end of the barrel and through a spring 55 encircling said stem and interposed between the nut 54 and the shoulder at the inner end of the stem. The outer end of said stem is furnished with a handle 56, preferably milled, by which the bolt 53 may be drawn outward against the pressure of spring 55, to withdraw itsv protruding forward end 57 from one or another of a series of holes 58 formed in a curved rib or projection 59 on the plate or cover 38. Arm 51 is furtherprovided with a' pin 60 to enter one or another of a second series of holes 61 formed in said arm. This 60, being small, pointed, and

eyond the protrudin end. of bolt 53, facilitates the alinement of said bolt with the holes or seats 58 made to receive it.

. Above the arm 51 and rib 59 is placed a dial -shaft 24 carries in addition to the sprocketwheel 23 which is keyed ortmade fast the-r on, a pinion 65, which is held against lateral play .or sliding upon said shaft, but has formed upon its side face one member 66 of a clutch. Also made fast upon shaft 24 at its ends, and extending from the hub of loose pinion to the bushing or hearing which carries the end of said shaft remote from wheel 23, is an encompassing sleeve 67 carrying a spline or feather 68. Slidable axially upon the sleevev67 is a gear 69, one face of which carries the second part of member 66 of the clutch already mentioned, so that when the gear 69 is moved to the left as the parts are seen in Fig. 4, it shall clutch with the pinion 65, and cause the latter to rotate with the shaft 24, sleeye 67 and gear 69. Pinion 6') meshes with a. gearwheel 70 pinned or otherwisemade fast to shaft 40; hence when gear 69 is clutched to gear 65, shaft 40 will be rotated by shaft 24 through the intermeshing of inions 65 and 70, giving one predetermine speed to the shaft 40.

Shaft 40 has keyed to it a pinion 71 with which gear 69 may be caused to engage when shifted to the right as the parts are seen in Fig. 4, the gear 69 being shown in neutral'position in said figure; that is to say, in a position in which it will neither clutch with the pinion 65 nor mesh with pinion 71. Gear 69 stands normally in the neutral position shown in Fig. 4. It may be shifted to clutch with pinion 65 or mesh with pinion 71, by swinging in one 01' the other direction the arm or lever 63, which is carried by a spindle 72 swiveled in a neck 73 formed on thecover-plate 38, and carrying at its inner end a radial arm 74, the outer end of which carries on a stud-axle a roller 75, seated in the grooved collar 76 formed on the hub of gear 69. When the gear 69 is meshed with pinion 71, rotary motion will be imparted from shaft 24 to shaft through said gear and pinion, giving a second speed ratio between said shafts. At such time all other connect-ions are of course inoperative between shafts 24 and 40.

Also carried by sleeve 67, slidable axially thereon, but held against independent rotation by the spline or feather 68, is a sleeve 77, carrying at one end a pinion 78, and at its opposite end a gear 79. Sleeve 77 is provided with a groove or channel 80 which receives a roll carried by an arm secured to the inner end of a second spindle swiveled in a tubular neck or hearing projecting from the inner .face of plate 38, and bearing at its outer end the second shifter lever 64. Pinion 78 when placed in plane therewith, meshes with a gear-wheel 81, the largest of a group or set of four keyed upon shaft 24, or upon a sleeve secured rigidly thereon, the next smaller gear being designated by the numeral 82, the larger pinion of the remaining two by the numeral 83, and the smaller pinion by the numeral 84.

Pinion 78 as shown in mesh with gear 81, at which adjustment it affords a third driving connection and speed ratio for shaft 40, but if moved to the left from the position seen in Fig. 4 it will be unmeshed from gear 81, while gear 79 of sleeve 77 will be moved first into plane with smaller pinion 84, which it cannot reach or contact with, and finally, on further movement to the left, into plane with larger pinion 83, with which it does mesh. This affords a fourth driving connection between shafts 24 and 40, and a fourth gear ratio, all effected by shifting of pinionsand gears 65, 69, 78 and 79 of shaft 24. Four changes may also be made by shifting the sleeve 45 and yoke 46 to place gear 49 into mesh with any selected one of the pinions and gears 81, 82, 83, 84 of shaft 40. Gear 49, being always in mesh with pinion 48, splined to shaft 41,- said shaft will be rotated at a speed controlled by the gear connections made as above explained.

As pinions and gears 69,- 78 and 79 may be put intotheir' several driving adjustments with pinion 49 in mesh with any one of the gears and pinions 81, 82, 83, 84,

sixteen changes are afforded, each giving a different speed to shaft 25, which receives motion through a gear 85, keyed to shaft 41, and meshing with a .gear 86 made fast upon shaft 25. As the grinding wheel 2 and shaft 24 are both driven by direct belt or drlvin band connection from shaft 14, there are a orded sixteen speed ratios between the grinding and governing wheels 2 and 3, since the governin wheel is driven through direct belt connect1on with pulley 26 carried by shaft-25.

It is of course understood that any suitable kind of flexible driving band may be employed, as leather or canvas, chain, rope, or other, though leather is preferred except in the case of band 22, which is preferably a sprocket chain of any suitable type or construction.

A motor for driving the grinding machine is shown in dotted llnes, to give a clearer idea of the complete machine, and truing devices for the wheels 2 and 3, means for effecting adjustment of slide and, wheel-carrier, and other features areshown for a like purpose. These are, however, made subjects matter of other applications.

By the construction 'above set forth we have produced a self-contained grinding machine of the centerless type, having a range of work hitherto neitherattained nor approached so far as we are aware, the ability to attain almost instantly any speed ratio between the grinding and the governing wheels enabling the operator or attendant to grind objects of'widely difl'erentmaterial, texture, hardness, diameter and form under conditions well suited to give the best results; and thiswhether manually inserting or removing, or manually inserting and removing the work, or manually inserting and automatically removing, or automatically inserting and automatically removing the work; whether the work is automatically fed axially through the machine during the grinding, or merely rotates without axial traverse; Whether the wheels are manually or automatically separated for introduction of work and approached to effect grinding to a predetermined extent, again. separated to free the finished workand to receive a fresh blank or object; and finally, whether the grinding be done on plain cylindrical work, headed work, shouldered work, or tapered work.

The change-speed gear also enables the operator to get a proper grinding and feeding rate with one fixed inclination of the governing wheel axis relatively to the axis of the grinding wheel, since though the inclination be slight, if the governing or control-wheel be rotated at a speed above the relatively low speed commonly used with centerless ders using the automatic axial or screw-l1 e feed, the work will be turned more rapidly, and though each rotation gives but slight advance, the rotations will follow so rapidly that the work will still be advanced at a. quite rapid rate, approximately the same as with greater inclination of axis but fewer rotations per minute. One machine is thus made capable of performing the several varieties of grinding heretofore requiring two or more distinct machines, which is a great advance in model shops and laboratories. where room is limited, or funds are small. It is likewise of great advantage in large factories employing many grinding machines, not only because the first cost, maintenance, repairs, etc, are reduced about one-half. but the full number of machines required can be placed in half the space required for two types of machines, yet any or all can be devoted to one class of grinding, or several kinds of grinding may be simultaneously done by different machines or groups of machines. The changespeed gear g hence performs a service in a centerless grmder of the character and having the features of interchangeability herein set forth,

that it does not perform in any other connection or relation known to us.

- What is claimed is:-

' 1. A centerless grinding machine containing within itself a grinding wheel; a co-acting governing or control wheel; an intermediate work-rest or support: a main driving shaft to receive power from a prime mover: a driving band connecting the grinding wheel pulley with said driving shaft; a second shaft receiving motion through direct connection with said main driving shaft: a third shaft; variable-speed gear interposed between the second and third shafts: a bandg wheel carried by said third shaft; and a band passing about said wheel and serving to rotate the governing wheel.

2.. A self-contained grinding machine,

comprising a grinding wheel; a co-acting governing or control wheel; a work-rest or support intermediate said wheels; a main driving shaft: direct driving connection between the said driving shaft and the grinding wheel arbor; and driving connections between the main driving shaft and the governing wheel arbor, including a variablespeed gear mechanism.

3. In a grinding machine, the combination of a main frame or base; a grinding wheel mounted for rotation upon said base; a governing wheel having its working face opposed to that of the grinding wheel, said governing wheel being adjustable toward and from the grinding wheel; a. work-rest or support located between the opposed faces of said wheels; a main driving shaft journaled in the base or frame; direct driving connection between said shaft and the arbor of the grinding wheel; a change-speed gear train; a driving band connecting the main driving shaft and a shaft of the change-speed gear: a shaft driven through the changespeed gear and provided with a band-wheel; and a driving band connect-ing the last-mentioned wheel and the driving pulley. of the governing wheel.

4. In a self-contained grinding machine. a main frame or base; a grinding wheel mounted for rotation upon said base; a governing wheel movable toward and from the grinding wheel; a workest or support located between the opposing faces of the inding and the governing wheels; a shaft located in the base of the machine and provided with a band-wheel; idler pulleys mounted in the adjustable carrier of the governing wheel; and a band passing about the pulley on said shaft; over the idler pulleys and about the driving pulley of the governing wheel arbor; whereby the carrier and the governing wheel from the 'nding wheel without materially affecting did tension of the driving band.

5. In a self-contained grinding machine, a main frame or base; a grinding wheel mounted for rotation upon said base; a governing wheel movable toward and from the grinding wheel; a work-rest or support located between the opposing faces of the 'nding and the governing wheels; a shaft located in the base of the machine and pro vided witha band-wheel; idler pulleys mounted in the adjustable carrier of the gov-- have signed our may be moved toward and 

